Thank you all. I detached for the first time yesterday. I didn't ring her to find out where she was or when she was coming home. I didn't say anything to her when she did come home. I didn't get angry or lose my temper. I watched telly, went to bed and got up for work the next day. I asked her if she was ok this morning and she apologised for her little blip and thanked me for not having a go.
I have to say I feel so much better today. Normally, I'm a mess. If she drinks today, she drinks today and that's her decision, not mine.